Recently, large-capacity resin containers are widely used as containers for holding or transporting cooking oil, condiment, drinking water and the like. Such containers are increased in weight when filled with liquid such as cooling oil. Therefore, for the purpose of convenience of carrying or the like, many resin containers having a handle attached on a body of the container have been proposed (e.g., see Patent Documents 1 to 6).
For example, in Patent Document 1, a technology of enhancing an attachment strength of a handle to a container is disclosed. In Patent Document 1, two laterally facing protrusions (attachment portions) are provided on a distal end of a lower attachment arm of the handle, and preform resin which corresponds to the protrusions is inflated to become larger than the final container size and then an operation of pushing the inflated preform resin back to a position corresponding to the final container size is performed.